Electrically conductive organic polymers are being practically applied as electrically conductive fillers for electronic devices making use of the property as semiconductor, electrochromic materials utilizing the changes of absorption wavelength at the time of oxidation or reduction, battery electrode materials, electrochemical active substances, antistatic and electromagnetic wave shielding materials, etc.
In particular, electrically conductive polymers such as polythiophene, polypyrrole and polyaniline are stable in the air, and those with the electrical conductivity of 100 S/cm or more are electrically conductive polymers suited to practical use.
These electrically conductive polymers are treated by doping for forming a complex of a dopant and an electrically conductive organic polymer in order to provide them with an electrical conductivity of more than 1 S/cm. As this treatment, in such electrically conductive organic polymers as polypyrrole and polythiophene, it is relatively easy to dope by using gaseous dopant such as iodine and arsenic pentafluoride.
In this method, however, as the dopant is released from the electrically conductive polymer with the lapse of time, and the electrical conductivity is lowered.
In another doping such as a method of doping with anions by an electrochemical technique, although the electrical conductivity is relatively stable, the treating process is complicated, and it is not suited to mass production.
Electrically conductive materials including polyanilines show a stable electrical conductivity by the use of inorganic or organic protonic acid as dopant, Japanese Laid-open Patent Publication Hei 1-131,288 discloses a method of preparing an excellent paint by dissolving such doped polyanilines or polymer of aniline derivatives in a solvent. The doped polyanilines or polymer of aniline derivatives, however, dissolve only specified solvents such as N,N-dimethylformamide and N-methyl-2-pyrolidone, etc. In addition, the coating film formed with the above-mentioned doped polyanilines have problems that the coating film hardness, resistance to solvent and resistance to chemicals are poor, that protonic acid as dopant effuses when it contacts with solvent or separates from polyanilines when it contact with alkalis, so that electrically conductivity falls. There is also an attempt to prepare a paint by dispersing divided polyaniline or polymer of aniline derivatives in paint binder without dissolving them in solvent. However, it is impossible to form a coating film good in electric conductivity and transparency, unless the above-mention polymers are dispersed in solvents thoroughly. Actually, a coating film which has good in hardness, electric conductivity and transparency has not been obtained as yet.
Japanese Laid-open Patent Sho. 60-60,166 proposes a paint which is cured by ultraviolet ray or visible ray in order to improve the hardness and resistance to solvent.
This paint is excellent in electrical conductivity and transparency, but since inorganic electrically conductive materials are contained, it is not easy to disperse the materials in the binder, a large amount of dispersant is needed, and moreover it takes a long time in dispersing them in the binder, and even after dispersing, because of re-coagulation, the storage life of the paint is poor.
Further, Japanese Laid-open Patent Hei 3-137,121, U.S. Pat. No. 5,378,403, U.S. Pat. No. 5,218,363, and U.S. Pat. No. 5,324,583 also disclose electrically conductive compositions containing anilinic polymers.
This invention is provided to solve the problems.
It is a primary object of the invention to present an electrically conductive paint composition capable of forming a coating film excellent in transparency, hardness, resistance to solvent and resistance to chemicals especially to alkali, being easily cured, and the paint composition being excellent in storability.
The other object of the invention is to present an antistatic transparent articles coated with electrically conductive film having such excellent properties as mentioned above.